Using the herb comfrey on teeth could be dangerous for health

25 April 2023
What was claimed

Comfrey stimulates regeneration of tissue in teeth and gums and should be used as a mouthwash every day.

Our verdict

There is no evidence for this. Using comfrey by mouth can carry risk of liver damage and links to cancer have been found in animal testing.

A Facebook video with over 10,000 likes and almost 5,000 shares contains dangerous information about using the herb comfrey for dental health. The original video had been viewed over 3 million times on TikTok before it was deleted. The original poster, ‘Raw Maraby’ has also posted other similar claims on Facebook.

The person in the video claims that “if you have gum problems and you have teeth problems and you want to fix it, there is a way to do it [...] Comfrey has been well studied. It actually stimulates regeneration of tissue, bones no matter what you put comfrey on it will start to regenerate.” 

He advises viewers to “just put it as a mouthwash or you can put it as a [sic] oil pulling, rinse, rinse your mouth, swish around your mouth, do it daily”.

The caption to the video contains a link to buy “Gum and Tooth Powder” that contains comfrey, advising: “For tough cases, place this powder between your gums and lips and leave it on all night, 7 nights a week”.

But Full Fact was unable to find any evidence that comfrey can help with dental health, and the plant can be very dangerous if taken orally.

A British Dental Association spokesperson told Full Fact: “There is no robust scientific evidence to suggest that comfrey can stimulate regeneration of tissue and bone, for gums and teeth. 

“In addition, comfrey contains pyrrolizidine alkaloids, toxic compounds that have carcinogenic effects, which can cause severe liver damage and even death, if taken orally.”

They confirmed that this risk applies to mouthwash due to the possibility of swallowing it, and absorption through any sores or cuts in the mouth, and added there is limited scientific evidence to support the use of comfrey as a herbal remedy for joint and muscle pain, as it is often used.

In 2001, the Food and Drug Administration told manufacturers to remove products containing comfrey or other sources of pyrrolizidine alkaloids and tell their customers to stop using them, or risk having their products removed from the market in the US.

The UK Food Standards Agency also recommends against consuming infusions made from comfrey.

In its list of harmful garden plants, the Royal Horticultural Society describes comfrey as “harmful if eaten repeatedly”. 

Bad information about health can cause direct harm if people consume dangerous or ineffective substances, or avoid doing things that could have been beneficial. We have previously covered false claims about potentially harmful substances being good treatments for disease as well as vice versa—false claims that useful medications are poisonous or harmful.

The NHS warns that herbal medicines can interact with other medications or medical conditions and advises to discuss with a doctor.

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What is comfrey?

Comfrey is a leafy, flowering plant that has been used for centuries in traditional medicine, mainly for injuries like broken bones and burns, as well as other ailments. 

But research has shown a significant risk of liver damage and a potential link to cancer in animal studies when eaten. 

Full Fact has contacted the original poster for comment.

Featured image courtesy of Michel Langeveld

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